Communication system

Abstract

A communication system is disclosed, in which a mobile telephone communicates user data substantially simultaneously via a first base station and a second base station of the communication system. The mobile telephone detects a problem in communications with the second base station and transmits, to the first base station on detection of a problem in communications with said second base station, an indication of the detected problem in communications with the second base station.

The invention claimed is: 
     
       1. A user equipment (UE), the UE comprising:
 a memory storing instructions; 
 one or more processors configured to execute the instructions stored in the memory to: 
 communicate user data, in a dual connectivity (DC) in which the UE is connected to a master base station and a secondary base station; and 
 detect a radio link failure for a secondary cell group (SCG); wherein, 
 on detection of the radio link failure for the SCG, the one or more processors are further configured to initiate a procedure to report the radio link failure for the SCG, upon initiating the procedure the one or more processors are further configured to suspend at least one SCG communication bearer associated with the SCG, the suspended at least one SCG communication bearer being a communication bearer having protocols located in a secondary base station operating a secondary cell but not in the master base station, and the secondary base station is connected directly with a serving gateway (S-GW) in a core network, and to provide an indication of a failure type, wherein said indication of a failure type is configurable to indicate any one of at least the following: a timer has expired, a random access problem, or a maximum number of Radio Link Control (RLC) retransmissions has been reached. 
 
     
     
       2. The UE according to  claim 1 , wherein the instructions for communicating user data are operable to: i) receive said user data via the master base station via a first communication bearer provided between said UE and the core network; and ii) receive user data via said SCG using a second communication bearer provided between said UE and said core network. 
     
     
       3. The UE according to  claim 1 , wherein the instructions for detecting a communications failure are operable to detect the radio link failure for the SCG. 
     
     
       4. The UE according to  claim 1 , wherein the instructions for communicating user data are operable to, upon initiating the procedure, initiate a handover of at least one communication bearer associated with the SCG. 
     
     
       5. The UE according to  claim 1 , wherein the instructions for communicating user data are operable to, upon initiating the procedure, suspend or release a MAC entity associated with said SCG. 
     
     
       6. The UE according to  claim 1 , wherein the instructions for communicating user data are operable to, upon initiating the procedure, suspend or release at least one serving cell in the SCG. 
     
     
       7. The UE according to  claim 1 , wherein the instructions for communicating user data are operable to, upon initiating the procedure, release radio resources for associated SCG communications. 
     
     
       8. The UE according to  claim 1 , wherein the master base station is a master eNB. 
     
     
       9. The UE according to  claim 1 , wherein the at least one cell of the SCG is operated by a secondary eNB. 
     
     
       10. A method performed by a user equipment (UE), the method comprising:
 communicating user data, in a dual connectivity (DC) in which the UE is connected to a master base station and a secondary base station; and 
 detecting a radio link failure for a secondary cell group (SCG); 
 wherein on detection of the radio link failure for the SCG, the UE initiates a procedure to report the radio link failure the SCG and upon initiating the procedure, the UE suspends at least one SCG communication bearer associated with the SCG, the suspended at least one SCG communication bearer being a communication bearer having protocols located in a secondary base station operating a secondary cell but not in the master base station, and the secondary base station is connected directly with a serving gateway (S-GW) in a core network, and provides an indication of a failure type, wherein said indication of a failure type is configurable to indicate any one of at least the following: a timer has expired, a random access problem, or a maximum number of Radio Link Control (RLC) retransmissions has been reached. 
 
     
     
       11. A non-transitory computer readable medium having stored thereon software instructions that, when executed by a processor, cause the processor to perform a method according to  claim 10 .